> For sandboxing arbitrary code in arbitrary languages, WASM is not yet viable. For sandboxing code you control the toolchain for, it is excellent.
That sounds pretty definitively like they're saying it is a great practical solution for many cases, not "ruling it out" like you mentioned in your top-level comment. It sounds more like they're saying it's not currently a black-box that you can run arbitrary code in, which is what some people might want in a sandbox.